Last month, South Korea hosted hundreds of world leaders for the globe's largest and most important conservation event – the World Conservation Congress. Although the gathering took place an ocean away, one of its goals – determining how to more sustainably meet the globe's growing need for good food – is highly relevant here in the United States, particularly in light of this summer's debilitating drought.

Worldwide, a billion people go hungry. A similar number over-eat the wrong foods. And yet one-third of food produced for human consumption is wasted.

Industrialized food production promised liberation from the constraints of Earth's natural cycles. And unfettered trade seemed to enable culinary abundance wherever there was money to buy it. But the over-use of fossil fuels, chemical fertilizers, and precious groundwater supplies has levied significant costs on our planet. We are now overshooting Earth's bio-capacity by 40 percent.

There's a better way. It's called agroecology, and it integrates scientific understanding about how particular places work – their ecology – with farmers' knowledge of how to make their local landscapes useful to humans. Only by re-orienting our approach to food production in this way can we begin to solve the food, energy and development crises afflicting our planet.

Industrial food production is destabilizing Earth's life-support systems. Every calorie it provides requires so much oil and gas to produce that our agricultural system generates nearly a third of the globe's greenhouse gases. And through massive use of fertilizer, we have disruptively tripled the nitrates in Earth's natural nitrogen cycle.

Soils have been treated as inert – and are consequently dying. The productivity of nearly half of all soil worldwide is decreasing. Another 15 percent can no longer be used for farming because its biology has been so depleted.

Biodiversity is fading, too. Eighty percent of the world's arable land is dominated by genetically homogeneous monocultures – that is, single crops grown over wide areas. Only weeds and pests can thrive in such environments.

The time for this rapacious approach has run out.

Agroecology, by contrast, celebrates the value of diverse and complex methods of land stewardship. The approach re-integrates livestock, crops, pollinators, trees and water in ways that work resiliently with the landscape.

Agroecological techniques replace the "vicious cycles" bringing down our planetary support systems with "virtuous circles" that mimic nature's own systems.

For instance, agroecology can restore soil fertility and sequester carbon naturally rather than spewing it dangerously into the atmosphere or as acid into the ocean. Its nutrient cycling approach – whereby nitrogen passes again and again through food systems, roots, and soils – can turn waste into raw materials rather than pollutants.

In essence, agroecology seeks out nature-based solutions by empowering farmers to do what they know works best on their own lands – and then to spread those lessons far and wide.

And agroecology is now set to rise beyond the fields of marginalized small landholders – and onto the global stage.

We can learn from examples like those set by farmers in Kenya, who have created a "push-pull" system to control parasitic weeds and insects without chemical insecticides. The system "pushes" pests away by planting insect-repellant species among corn crops while "pulling" pests to plots of napier grass, which excretes a sticky gum that attracts and traps insects.

The results have been remarkable. "Push-pull" doubled yields of maize and milk and is now used on over 10,000 farms in East Africa.

Such results can scale up. One study examined 286 agroecological projects covering 37 million hectares in 57 poor countries. Researchers found that these interventions increased crop yields by a stunning 79 percent.

But agroecology doesn't just increase the output of farms. It also values farmers' relationships with and knowledge of their lands – and does not treat them as passive recipients of aid or external inputs. As such, it is a powerful, cost-effective and sustainable model for development.

The industrial agriculture experiment of the 20th century has failed. With agroecology, we now have an approach that can endure. Its small farmers can feed and cool the planet – and follow ways of life they value. Our leaders must support such food systems that truly nourish people and the planet.